2010·宁夏银川·二模
1 . 有下列命题:
①设集合M= {x| 0<x ≤3},N= {x| 0<x≤2},则“a∈M”是“a∈N”的充分而不必要条件;
②“
”是“
”的必要不充分条件;
③“
”是“直线
与直线
互相垂直”的充要条件;
④命题P:“
”的否定
:“
”.
则上述命题中为真命题的是
①设集合M= {x| 0<x ≤3},N= {x| 0<x≤2},则“a∈M”是“a∈N”的充分而不必要条件;
②“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbe67ea1bdf1a7148ee8ae4ff3ead173.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43ca23776458f8f9f9f84c4b0a73ad2c.png)
③“
![](https://img.xkw.com/dksih/QBM/2010/5/23/1569744032735232/1569744037732352/STEM/3b34db3312cd4e7eb054f07083432634.png?resizew=36)
![](https://img.xkw.com/dksih/QBM/2010/5/23/1569744032735232/1569744037732352/STEM/8d7530c68b5f42de88c6ee7308a80fa9.png?resizew=68)
![](https://img.xkw.com/dksih/QBM/2010/5/23/1569744032735232/1569744037732352/STEM/3bea99cbb2b740ffb5396d3b54e865d1.png?resizew=69)
④命题P:“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bea4cdab4528a4595dfd89c024be88c.png)
![](https://img.xkw.com/dksih/QBM/2010/5/23/1569744032735232/1569744037732352/STEM/9b2fe7f2217348ff98734c660f15245c.png?resizew=25)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/909d46c1d579713c79ce76708ca70a94.png)
则上述命题中为真命题的是
A.①②③④ | B.①③④ | C.②④ | D.②③④ |
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